The direct economic costs of insomnia in the United States exceeds $15 billion per year. Up to 50% of the population over 65 years suffers from chronic insomnia. The result is both compromised health and a reduction in the quality of life. The magnitude of the problem is underscored by the fact that approximately 40% of hypnotic medications are prescribed to individuals over 60 years of age, and the proportion of use increases with age. The features that make up age-related sleep disturbance are suggestive of a circadian rhythms involvement, and growing evidence suggests that timed exposure to bright light can be an effective treatment for this disorder. Yet, previous work makes it clear that bright light treatments could be more beneficially applied if greater attention is given to specific physiological and behavioral factors that intervene to limit efficacy. The current application seeks to take advantage of recent findings which suggest that a low-maintenance treatment strategy that controls judiciously an individual's exposure to light throughout the 24-hour day may be critical to making this promising non-drug approach more effective. Using a lab-based assessment and in-home treatment approach, we will examine the effects a home ambient light operating system (HALOS) on the sleep quality and waking function of a group of older subjects with sleep maintenance insomnia. Development and implementation of this safe, affordable and easy-to-use approach for the effective treatment of age-related sleep disturbance will make a significant positive impact on the quality of life of individuals suffering from the disorder, while reducing the substantial economic cost to our health care system associated with the treatment and consequences of age-related insomnia.